Dentist assistants and hygienists of dental department are the members of medical group of dental department. In Taiwan, there were the graduates of Dental Hygiene departments participating in the service in the medical group of dental department for assisting the dentists with the treatment of the patients with dentist assistants. However, currently, there was no related laws and regulation with regard to the definition of dentist assistants and hygienists of dental department. Therefore, their roles and working scale were similar. The professionals thus could not benefit the people with professional standard. For the professionals with dental specialty cultivated by educational system of the country, it was actually a pity. Therefore, at the time of the gradual formation of national assistants of dental department, the researcher collected the related information of dentist assistants and hygienists of dental department among America, Canada, Japan and Hong Kong including the working information such as the origin of hygienists of dental department, educational system, registration of certificate, working content, working area and salary as the reference for teaching in academic circle and lawmaking of administration institutions.